1. Field of the Invention
The present invention relates to an energy absorbing wiper system for a vehicle.
2. Description of the Related Art
Among wiper systems for a vehicle, there is known a wiper system having an energy absorbing system for absorbing an external force when it is applied thereto to thereby minimize damage to the wiper system itself or a vehicle body panel. Referring to FIGS. 15, 16, the wiper system having the energy absorbing structure will be described. In the figures, a cylindrical pivot shaft holder 2 is fixed to a vehicle body panel 1. A pivot shaft 3 is rotatably inserted into the pivot shaft holder 2, and a lower end of the pivot shaft 3 is connected to another pivot shaft (not shown) by a link member 4. On the other hand, a proximal end 6 of a wiper arm 5 having a wiper blade (not shown) attached to a distal end thereof is fixed to an upper end of the pivot shaft 3.
A washer 8, which is restricted with respect to an upper movement by a snap ring 7, is mounted on the pivot shaft 3 at a substantially central portion thereof in a vertical direction. This washer 8 is retained to a retaining plate 9 mounted to a circumferential portion of an upper end of the pivot shaft holder 2. In addition, a cylindrical support member 10 is interposed vertically between the pivot shaft holder 2 and the pivot shaft 3. This construction is disclosed in JP-A-II-301420.
Consequently, when an external force is applied to the pivot shaft 3 from above and the external force exceeds the rupture stress of the retaining plate 9, the pivot shaft 3 which is in a condition shown in FIG. 15 is forced to sink into the pivot shaft holder 2 as shown in FIG. 16 by the shear fracture of the retaining plate 9.
In the related art, while the breaking load of the retaining plate 9 can be set as desired by modifying the strength and rigidity thereof, the problem with the prior art system is that space is wasted because space must be provided to secure a sinking stroke of the pivot shaft 3 into the pivot shaft holder 2 so as to avoid the bottoming out of the pivot shaft holder 2 when the retaining plate 9 is broken.